Today the Bluetooth SIG formally adopted the full specification for Bluetooth low energy and made it available for public download. It’s exciting – they’re firing the starting pistol for a new ecosystem of innovative products and applications that will change the way we think about the things around us.

Bluetooth low energy is not just a variant of the existing Bluetooth specification – it’s an entirely new standard that’s been optimised for low power and internet connectivity. It marks a step change in short range wireless, providing a new short range connection for a new decade.

That may sound somewhat overblown, but it’s true. If you look at other wireless standards they differ mainly in topology. Bluetooth classic (the one you’ve already got) is mostly used as a simple cable replacement to connect two devices to each other, whether that’s a headset, a games controller or a milking machine. Wi-Fi connects devices to a static access point, which can then link them to a broadband connection and ZigBee connects a collection of devices together into a mesh. If you want to do anything other than that with any of them, it’s quite difficult.

Bluetooth low energy turns a lot of conventional wireless thinking on its head. It is a very asymmetric design, allowing you to make very simple devices, which can be very cheap. These spend most of their life asleep, waking up occasionally to send data about themselves to something like a phone, a PC or a home gateway. They ask these devices to forward that data to the internet, allowing them to function as web-connected products which can interact directly with web applications. When they’re not doing that they go back to sleep.

These may seem a minor difference, but it has a profound effect on the way that you can design devices. The fact that they sleep most of the time, means that they are very, very low power. For many applications they can run off a small coin cell for years. It means that the battery essentially lasts for the life of the product. So you can design connected devices that never need charging. If you don’t want a battery, you can use a tiny solar cell instead. Bluetooth low energy takes a fraction of the power of other so-called low power wireless technologies. The chips are so small, that a complete product can be made that’s the same size as the coin cell that powers it, and only a few millimetres thicker.

When they talk to a phone, they can display their data on the phone, or ask the phone to send it on to the net. If the phone supports downloadable applications, then the device can tell it which apps to offer to the customer, making it even easier for them to load them. In other words, it’s an architecture that’s designed for the new world of apps stores and the internet of things.

Blueooth low energy has taken a long time coming, but there are good reasons for that. It first started life nine years ago in 2001, when it was presented by Nokia as a potential option for 802.15.4. That’s the standard that eventually grew to spawn ZigBee, 6LowPAN, and a host of other radios. Nokia’s proposal wasn’t accepted, so they continued to develop it with local partners, before launching it on the world as Wibree. From there it was transferred to the Bluetooth SIG under the name of Ultra Low Power, from which it morphed into Bluetooth low energy.

It’s turned out to be a fruitful journey. From the start, it had a different premise to other wireless standards. Even back in 2001, Nokia’s vision was that it would be a low power radio that would allow everything that we carry with us or have around us to connect to a mobile phone. Whereas other radios have had their market expectation set by the number of devices they can fit into (five billion for mobile phones, one billion for PCs), by using the mobile phone as a hub, the expectation was that this was a radio whose potential could be trillions of devices.

But if it was ever to get to that volume, or even to tens of billions, everything about it had to be right. It needed to be the lowest power of any radio; it had to be the most robust against interference; it was vital that it was the lowest cost; interoperability was imperative, as was security and it had to be easy to implement. Putting all of that together was not an easy task. And it took time.

The prospect of what it could do galvanised the industry. RF experts who had previously been involved with proprietary low power wireless chips joined in to add their expertise. So did those who had designed the ultra low power radio behind ANT. Drawing on the expertise of its 13,000 member companies, and its own experience of eleven years of wireless design, the SIG took the bold step of giving those designers a largely blank sheet of paper with the task of designing the best low power radio and protocol stack in the world. Today the resulting specification has been adopted and I believe it is very much fit for purpose.

The task now is to put the chips and development kits into the hands of innovative designers and let their imagination run riot. Anything that we touch or use can employ Bluetooth low energy to send its data to the net. When you fill up a beer glass it can tot up your total on your Facebook page. Your new remote control can work with any piece of audio or video equipment in the house. When you lose it down the side of the sofa, you can find it using your phone. Your mouse can run far longer on its batteries (limited only by its optical sensor), and with the advent of new medical sensors, it can send your pulse to your GoogleHealth record whilst you’re struggling to install Microsoft’s latest upgrade.

What gives it an unfair advantage over any other wireless standard is its ability to talk to the next generation of Bluetooth chips in mobile phones. In a few years these phones will act as internet gateway for billions and then tens of billions of connected devices. It’s the technology that the sports and fitness market have been waiting for, as has the consumer health industry. It also gives the smart energy market a real standard to work with that will be ubiquitous in the Home Area Network, where it will gain dominance through its position in the mobile phone and remote control.

And it has one more trump card – it has a roadmap to a price point that has the potential to decimate other wireless standards. When Bluetooth chips first appeared on the market, they cost around $20. Ten years later, in volume, that price has fallen to $1, driven by the volume of a billion chips per year. Bluetooth low energy was designed to be low cost, even in low volume. Today, for initial small volume applications, Bluetooth low energy chips will cost a few dollars. Over the coming years, as it follows the same volume path, that’s projected to fall to less than 20 cents. It’s the only way any technology can get to the trillions. It means it will become cheaper to use Bluetooth low energy as a wireless link than it will be to use a cable and connector. In cars and household appliance, it will be cost effective to replace cables between front panel controls and displays and the control electronics inside them, which means it really will make sense to have Bluetooth in your fridge. And the same chip can connect to the net to provide maintenance data, giving double value. Effectively, connectivity becomes free.

It promises to be a revolution in the way products are designed and used. If successful, it will do to connectivity what microprocessors did for control and applications. The Bluetooth SIG has provided the standard. It’s time to add your imagination.

I was alerted to the ANT FAQ this week by a couple of companies within the ANT community, suggesting it was new. However, that doesn’t change the basic argument.

Whilst I’d agree that the silicon may be similar, or even the same, that doesn’t necessarily get reflected in the pricing. A large part of the cost of chip development is in the associated firmware, production test equipment, test coverage and certifications. Those tend to get reflected in shipment volume. So although a Bluetooth basic rate + low energy chip may have the same die as a Bluetooth basic rate + low energy + ANT chip, the cost charged to the market is likely to be very different. At the volumes going into phones, silicon vendors will charge a considerable premium for a feature that needs additional support.

Once it is in the phone, the handset vendors then need to provide the higher layer stack and applications, ensure that all of the radios coexist happily together and get them qualified. That’s a strong incentive against incorporating new features, as support for multiple radios and protocols can rapidly turn into a support nightmare.
At the end of the day, all of this gets driven by market demand – from one end by what the technology roadmaps are of the handset companies, and at the other by what customers are buying in terms of fashionable accessories. As I said, both ANT and Bluetooth low energy need to prove their place – neither can take it for granted. However, I see lots of handset companies working on Bluetooth low energy stacks. I haven’t seen yet them working on ANT.

[…] Integrating standards based radio like Z-wave, ANT, Bluetooth and BLE will be necessary where interoperability is important. However, in many cases, the penalty paid in cost and performance will point to a customized RFOS solution. Even in cases where interoperability is necessary, there are instances where we have found that a second RFOS radio increases performance and can reduce overall system cost Today, for initial small volume applications, Bluetooth low energy chips will cost a few dollars. Over the coming years, as it follows the same volume path, that’s projected to fall to less than 20 cents. Nick Hunn […]

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About Creative Connectivity

Creative Connectivity is Nick Hunn's blog on aspects and applications of wireless connectivity. Having worked with wireless for over twenty years I've seen the best and worst of it and despair at how little of its potential is exploited.

I hope that's about to change, as the demands of healthcare, energy and transport apply pressure to use wireless more intelligently for consumer health devices, smart metering and telematics. These are my views on the subject - please let me know yours.

Essentials of Short Range Wireless

A helping hand for wireless designers

Adding wireless connectivity to a product is a major challenge for any designer. There are so many new concepts, and a plethora of suppliers claiming they’ve solved them for you. I’ve tried to distil 20 years of experience into this book to help you get over the pitfalls, ask the right questions and make sure you understand the answers.